DE2332527C2 - Pressure sensitive imaging materials - Google Patents

Description

The invention relates to a pressure-sensitive image generation Materlal that instead of one multiple usable carbon paper sheet and instead of reusable one, two or more colored ribbons can be used for office and data processing machines.

So far, the most widely used types of paper are carbon paper made of a load-bearing fiber base on which a mixture of waxes, oils and color-releasing substances Pigments and / or dyes is applied. A part of this becomes through the pressure of type or pen Transfer mixture to an adjacent surface of paper or other image-receiving matertal.

These conventional carbon papers have the following disadvantages:

'. The amount of wax-like mass on a thin so Tissue paper can be applied. Is due to their peculiar fragility and the peculiar lack of cohesion of such masses which peel off when they are in a layer that is too thick is limited.

2. The thin tissue paper, which is in the interest of quality and the number of copies that can be made with it is required, is easily damaged by the type stop or by pen pressure. bo

3. The transferred, image-forming part of the waxy Printing ink remains on the surface and penetrates the fibers of an adjacent image receiver not a. From there he will be handling easily wiped off and so makes the copy M blurry and smeary.

Today's most common, reusable ribbons for office and data processing machines consist of a color-soaked carrier fabric such as cotton, silk or synthetics. A liquid one Printing ink made from non-drying oils, dyes and / or pigments is adsorbed by the capillaries Pores of the yarn and held in the open spaces between the individual threads. Such, several times Usable, color-soaked tapes have the following disadvantages:

1. Due to the thickness of the woven fabric (0.1 to 0.13 mm), a sharp image with good definition, as is essential for copies and for optical character recognition, cannot be obtained.

2. The liquid printing ink with which the fabric is saturated Is easy to peel off and stain the fingers of those who have to handle it.

3. Since printing ink is present on both sides of the tape, the type areas decrease in the course of the Tent printing ink and loose fiber particles that clog the type surfaces. Clogged by such Images generated from type areas have very poor character sharpness.

In the last tent are improved so-called "solution carbon" arches and ribbons for office and data processing machines came onto the market which the image-forming layer consists essentially of a continuous plastic phase with sponge-like There is properties that allow a thicker coating with a longer service life, and one liquid or semi-liquid, discontinuous, color-releasing phase. The expression "solution carbon" guides from the fact that the synthetic resin is only dissolved in a suitable solvent before application become nrjß that you let evaporate afterwards. Since in use only the liquid, color-releasing phase or Printing ink is transferred, this printing ink penetrates approximately under the surface of an adjacent, porous Image receiver and thus produces a clean copy.

These new materials have certain features compared to known sheets of carbon paper and color ribbons Advantages, but also have the following major shortcomings:

1. If they are left between carbon papers, so the In the sponge-like, synthetic resin holder, Imaging layer, liquid or semi-liquid printing ink is suspended and wiped off from the paper, so that the latter becomes stained and the layer's own intensity is greatly reduced will.

2. The cleanliness left a lot to be desired, as the Handle printing ink is easily dispensed.

3. Since the proportion of resin-containing binding agent in these systems is quite low - usually between 25 and 30% by dry weight -, the transfer layers have low strength and cannot withstand repeated pressure from type or pen for long.

In order to remedy the last-mentioned disadvantage, one uses as a support base for some such image-generating materials various non-fiber films in place of the tissue paper. But also such As reusable office belts, foils are only used to a limited extent

found, because on many of the typewriters in general use the type surfaces have such sharp edges, that they even puncture or puncture a very high strength carrier base film and cause it to tear. Furthermore, due to the method used to manufacture these imaging sheets, two-color sheets can be used Making tapes with great difficulty; they never appeared to any noticeable extent on the Market.

It is accordingly the object of the invention to provide a pressure sensitive, durable and practically non-smeary one To create imaging material and to find a method for its production which, instead of conventional, Reusable carbon paper or the like, instead of monochrome ribbons for office and Data processing machines' and are used instead of two or more colored ribbons for office machines can.

The imaging material of the invention consists of a primer layer on a flexible one Carrier base, an image-forming layer over this primer layer of essentially an ink-releasing, lyophobeii dispersion of pigments and / or dyes in an oil or plasticizer that am Bottom of the imaging layer is concentrated, and from a synthetic resin-containing portion of at least an, optionally plasticizer-containing synthetic polymer, which is essentially at the top of the Imaging layer is concentrated and contains many tiny capillary openings in the binder, which are sized as 3 " Serve reservoir for the dye-releasing substance and enable the latter by application of Pen or type printing is squeezed onto an adjacent image receiver.

According to the invention, a suitable base paper or a non-fibrous film can be coated with a synthetic resin-containing primer layer which adhesively binds the image-generating overlayer. Preferably, such a synthetic resin-containing primer layer also contains some primary softener for the synthetic resin from 0.5 to 996 and from -0 to 40% of a coloring pigment. The latter has the purpose of giving the rear side of the end product a pleasant appearance which differs from that of the image-forming layer when a transparent film is used as the support base. Such a different appearance is not only important for aesthetic reasons, but also serves to eliminate those end products that are inadvertently lacking the primer layer. In attempts to improve the appearance of lint paintings- "zeugungsmaterlallen 'by adding various pigments and metal powder for Grundlerungsschlcht was found that imaging layers which have been applied to primers, which distributes between 25 and 55% of their dry weight finely a nlchtblättern- ⁵⁵ of the metal powder surprisingly adhered contained much better in such primers. It is believed that this phenomenon is probably due to the fact that nlchtblätternde metal powder of the Grundierungsschlcht impart a greater free ⁶⁰ Oberflächenenergle and thereby improve both the uniform distribution as the penetration of the Bllderzeugungsschlcht and therefore create the conditions for a better bonding effect.

IIIn essential feature of the kunstharzhaltlgen bond demlttels ⁶⁵ inspects the fact that it may be used in the plasticizers of Bilcierzcugungsschicht not be soluble, to cause no reduction in Blldlntcnsltät characterized in that the plasticizer migrates into the Grundlerungsschicht.

Another essential feature of the primer coating is a sufficient thinness so that an intimate contact between the coating and application side of the carrier base.

The required viscosities can be obtained using one of the following methods:

1. Dilution with suitable thinners, after application in a drying tunnel be expelled;

2. Heating the primer coating above the setting temperature the synthetic resin binder;

3. Combination of both methods.

Since most large-scale, non-fibrous base materials have very smooth surfaces, What is detrimental to a good connection, it is furthermore essential that a film surface is more sufficient Rough to get a good connection between to ensure the carrier substrate and the connecting, liquid primer coating.

In a method for producing such a rough Surface, the film is guided over a roller with an abrasive surface, with speed and Can change the direction of rotation of this role. By choosing the speed of the scrubbing roller, your direction of rotation and The degree of roughness can be strongly influenced by the contact angle of the web.

Another method is to use the desktop of the Base foil treated with a corona discharge. Such a treatment also ensures adequate treatment Roughness of the surface of a thermoplastic base material, making it penetrating and uniform Spreading of the primer coating is much easier and therefore favorable conditions for a good binding effect creates.

In a preferred application method, the primer coating is first pre-dosed onto a roller that runs at exactly the same speed as the road. The priming material is applied to this role squeezed by a pinch roller, the one with the back the railway is in contact. The purpose of this squeezing pressure, which depends on the conditions is to improve the penetration and even distribution of the primer coating. By using this application process, the pre-dosed primer coat is largely but not completely transferred to the web. A Part remains on the application roll, so that the layer tears open at the coating / application roll interface entry. On these catfish tiny scars or sieve marks are produced on the bottom layer so that an artificially rough surface is created for the subsequent casting of the imaging layer. Naturally the flow, drying and / or solidification conditions of the coating must immediately follow Its application must be chosen so that the coating, which is still liquid, cannot level out, thus reducing the surface roughness is retained even after the coating has hardened.

In another embodiment of the invention the primer layer containing synthetic resin is made of thermoplastic Synthetic resins with good flow properties at elevated temperatures are selected. If the Primer coat according to the above-described

After a process has been applied, a thermoplastic film base is applied to the coating interface melt easily and thereby fuse with the primer, making a very satisfactory bond, even if that difficult Adhesive materials such as polyolerine foils are used as the carrier substrate.

In another melt process, a thermoplastic primer can be selected from aqueous synthetic resin dispersions. After the water has been evaporated by forced drying, the coated base film is exposed to an ultra-red heat radiation of an intensity which is sufficient to to fuse the base layer with the base film

In a further embodiment of the invention - and in particular when a high film strength is desired - the synthetic resin-containing primer binder is selected from thermosetting or chemically crosslinking synthetic resins, which Finished product impart high impact resistance and at the same time satisfactory both on the carrier and adhere to the imaging substrate.

Representative compositions for the primer layer are as follows:

Example I. Thermoplastic solution type:

12 parts of polyvinyl acetal 4 parts of dicyolohexyl phthalate plasticizer, 8 parts of non-flaking aluminum powder 42 parts of ethanol, 95%

34 parts of toluene

100 parts

Example II Thermoplastic Hot Melt Type:

40 parts of polyvinyl acetate / polyethylene mixed polymer, 15 parts of polyisobutylene

25 parts of low molecular weight polyethylene 10 parts of hydrogenated castor oil 10 parts of paraffin wax

100 parts

Example III Thermoset Helßschmelztyp:

25 parts phenolic resin

25 parts of tri-phenyl phosphate

10 parts glyceryl ester of a hydrogenated resin 20 parts of polyvinyl acetal

20 parts hydrogenated castor oil

100 parts

Example IV

Network type:

6 parts of polyamide resin

6 parts epoxy resin
14 parts bronze powder
12 parts non-flaking bronze powder, 26 parts toluene
16 parts isopropyl alcohol
20 parts Methvläthvlkoton

The image-forming layer according to the invention consists of a synthetic resin-containing binder dissolved in certain solvents, certain finely dispersed pigments and / or dyes, certain oils, which serve as solvents for the color-releasing components, and, if necessary, certain primary plasticizers.

The following relationships among the various components of the imaging layer ίο are essential features of this invention:

1. The solvent system must contain at least one low-boiling main solvent and one higher-boiling auxiliary solvent;

2. The high-boiling solvent must be 25% by weight of the Do not exceed the low-boiling solvent;

3. The low-boiling solvent must not be used with the high leather, or at most only to a very large extent to a limited extent form an azeotropic mixture;

4. The low-boiling solvent must preferably be able to dissolve the synthetic resin- containing binder and the primary plasticizer;

5. or secondary plasticizers, or oils must, together with the pigments and / or color materials a lyophobic dispersion within the form and slightly below the surface of the resinous binder.

00 parts

While it has heretofore been common, the ratio between the binder and the inconsistent, ink-releasing agent Limit the proportion of the system to about 1: 3. According to the invention, it is possible to use this ratio can be increased up to 2.5: 1. This is achieved in the following ways:

A carrier substrate made of paper or film, which is primed in the manner described above may or may not be, but in the case of a substrate consisting of a film with a primer coating has undergone a corona treatment, after applying the primer coating a mixture of solvents, binders, plasticizers and pigment and / or dye. When the low-boiling solvents evaporate inside a drying tunnel, they cause an Because of their greater dissolving power for the binder system that the greater part of the binder to free surface is conveyed where a continuous

so film is formed. With further heating, the high-boiling auxiliary solvent through this film driven through; a so-called "run-up" surface remains, which consists of many capillary openings In this film exists. It can then not only be the underlying. liquid, color-releasing phase through pen or type printing can be pressed out of these capillary openings - like printing ink from one ordinary fabric tape is squeezed out - but it also changes c'le color of the surface in

fco is a much lighter shade than the underlying Create pigments. This is due to the fact that the initially existing transparency of the 'clear Oberllächc by the evaporation of the low-boiling Solvent formed by the subsequent

^h 'following evaporation of the high-boiling solvents and the formation of the capillaries is destroyed. In this way it is possible to create a black or intensely colored image with the help of a color-releasing medium

10

whose surface can in reality be white. Even if the free, tarnished surface of the new product gradually darkens with use, it is but cleaner and more durable than any similar product known so far, as it has a higher resin content Has.

Representative examples of the casting compound of the image generation layer are the following:

Example V

11 parts of polyvinyl acetal resin made from butyraldehyde
2 parts of isooctyl-benzyl-phthalate main detergent
7 parts rapeseed oil - inconsistent plasticizer
6 parts of toluene red is

68 parts of chloroform - low-boiling "aupilösungs-

middle
6 parts of xylene - high-boiling auxiliary solvent

Example VI

ABS polycarbonate alloy
Ester-like plasticizer - main plasticizer butyl stearate - inconsistent plasticizer
soot

Molybdate Blue - clear organic dye Methylene chloride - the main low-boiling solvent

Isobutyl alcohol - high-boiling auxiliary solvent

100 Parts 10 Parts 6th Parts 8th Parts 5 Parts 1 part 62 Parts 8th Parts

100 parts

Example VI

arrest sheet results.

It is also possible to apply a second overcoat to a self-supporting imaging layer prior to stripping pour up. A synthetic resin can be selected for this, which gives the product even greater flexibility and gives strength.

This seals the surface of the film; it no more printing ink can be released through them. Because the side facing the viewer was originally unglie was facing the Trägerbasls-Folle and with your higher ink concentration is now the rare thing to produce images products made by this process are suitable due to their greater smeariness this area does not do particularly well than carbon paper because of the close contact that such sheets have To be used with the carbon paper attached to have. However, their use as an office machine belt is ideal, as type surfaces that can only be used with the clean Contact with the side, do not accept the ink and always stay clean.

Successful reinforcement documents are made up of the following Solutions have been poured:

Example VIII

12 parts ABS polycarbonate alloy
2 parts Hauptwelchmacher polyester-like plastic bottle

rer

40 parts of chloroethane
28 parts of methylene chloride
18 parts of toluene

100 parts

Is to produce a particularly thin imaging film that produces particularly sharp images and of the longer length on the core of the coil of an office machine can be wound, it is possible to use a coating compound e.g. B. according to the above examples, which, however, advantageously contains an even greater content of synthetic resin-containing binders a previously untreated polyolefin film base or another substrate with good release properties

17 parts cellulose acetate 9 parts dloctyl sebacate - inconsistent plasticizer 7 parts of Aikaiibiau

60 parts of ethyl acetate - the main low-boiling solvent
7 parts of naphtha - high-boiling auxiliary solvent ⁴ <> 100 parts

Example IX

14 parts of acrylonyl-butadlene-styrene copolymer

40 TeUe of toluene

36 parts of trichlorethylene

100 parts

Example X

11 parts polyvinyl acetal resin made from formaldehyde
3 parts main plasticizer, polyester-like plastic film

smaller
Sn parts of trichlorethylene

100 parts

According to another procedure, it is within the Within the scope of the invention it is also possible to use an image generating material (as described) with a carrier base made of non-fibrous materials such as polypropylene,

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separate the two lanes by peeling and each of the two on a separate spool. The now self-supporting film can then be cut and opened various office machine reels are wound while the carrier web is reused many times for casting can be.

In contrast to previously known imaging films of this type with their comparatively low binder content Self-supporting foils produced using the new process have a much higher tensile strength and impact resistance. In addition, their ink holding capacity is also considerably larger, because the capillaries in the foil are able to hold a much larger amount of a thinner printing ink or to adsorb, which results in lower wear and better penetration into the image or the like with a primer and an image generating layer and then the back of the carrier base film with another, different one Type of film to conceal. In this way, the most favorable properties of a carrier base, such as tensile strength, Impact resistance, toughness and flexibility that used to be mutually exclusive in a single base film excluded, easy to combine. It is particularly preferable if the thickness of such pads and also that of the carrier base film with a total thickness of the laminated imaging material of 25 μm to 76 μm between 6 μπι and 30 μπι is.

Applying a reinforced underlay to the original base film is particularly advantageous when when two-tone office machine tapes are to be produced. In this case, the original image

production material with only one carrier base film ζ. B. 125 μίτι thick, stretched polyester oils with something Cut into half-length ribbons less than half the width of the final product. Another coil of the same Material, but of a different color, is then cut in the same catfish.

Two narrow ribbons of different colors are then placed on a full-width backing belt of approximately 25 µm thick, biaxially oriented high-density polypropylene film laminated next to each other. The one in Adhesive used should preferably belong to the crosslinking type 100 parts, which is not just a permanent bond between the two films, but also contributes to the strength and impact resistance of the product. Two adhesives that apply to two such films that are on

IUm .. L ' _nn (nb «n» ^ UAM! *> ·. "* I, rvr Aam V η ο r * I-» I α ra η Hiir ^ K

1111 \ r 1 1 i ^^. \ J 11 ί CL I \ LIl ClW 1IW 11 ^ V ^ J t tw V ^ f M ^ J ^ y lit I ^ U ^^ 111 Wi ^^ 11 ^ 4 u ι w 11 Corona discharge that have been treated well are the following:
Recipes used to laminate ribbons when making iQO parts of a two-tone ribbon:

Example XI

9 parts of H art-Acrylic resin

6 parts of the copolymer polyvinyl chloride polyvinyl acetate

5 parts of urea-formaldehyde resin, 10 parts of ethylene glycol monomethyl ether 70 parts of methoxide ketone

Example XII

8 parts of epoxy resin, 8 parts of polyamide resin, 52 parts of methyl ethyl ketone 32 teloluene

Claims (5)

Patent claims: 1. Pressure-sensitive, reusable image transfer material, consisting of a flexible one Carrier base, a: r primer layer on this Base and an image transfer layer on the primer layer, the image transfer layer a color-releasing, lyophobic dispersion of pigment-containing substance in a plasticizer and on their upper side facing away from the support base, capillary openings as a reservoir for the dye-releasing substance has, characterized in that the synthetic resin-containing primer between Contains 25 and 55% of their dry weight in finely divided, non-flaking metal powder. 2. Image transfer material according to claim 1, characterized in that the metal powder is aluminum or bronze powder is chosen. 3. Image transfer material according to claim 1 or 2, characterized in that the primer layer contains from 0.5 to 9% plasticizer. 4. image transfer material according to any one of the preceding claims, characterized in that the Primer layer contains a thermoplastic synthetic resin. 5. Image transfer material according to one of claims 1 or 3, characterized in that the Primer layer comprises a thermosetting or chemically crosslinking synthetic resin. 30th